DE102010028776A1 - Optoelectronic semiconductor component - Google Patents

Abstract

The optoelectronic semiconductor component uses a component made of metal phosphate. This is essentially free of alkali and halogen components. In particular, this metal phosphate is used as an adhesive.

Description

Technical area

The invention is based on an optoelectronic semiconductor component according to the preamble of claim 1.

State of the art

The DE-A 10 11 8630 and DE-A 10 15 9544 reveal LEDs with glass components. The US-A 5965469 discloses a phosphate glass used as an adhesive

Presentation of the invention

An object of the present invention is to provide a particularly temperature and weather resistant bond or components in an optoelectronic semiconductor device such as an LED according to the preamble of claim 1.

This object is achieved by the characterizing features of claim 1.

Particularly advantageous embodiments can be found in the dependent claims.

The present invention solves the problem of providing a bond or components in LED that are temperature and weather resistant. Such components increase the efficiency and lifetime of LEDs.

So far, LEDs are usually made with the inclusion of organic components, in particular that applies to the board, the lens or even for conversion elements of the LED. Moreover, an adhesive is often used in organic adhesive, for example, to attach a glass lid or glue a conversion element on a chip.

Such organic components typically have poor thermal conductivity and low UV resistance, especially as regards radiation resistance in the region below 420 nm. In addition, they are sensitive to temperature. Ultimately, all this leads to low efficiency because the LED is discolored or operated at too high a temperature.

According to the invention, a metal phosphate is used for bonding, or components of metal phosphate are used. This achieves improved thermal conductivity and better UV resistance. The metal phosphate is preferably lead-free or lead with a content of less than 1 mol%.

Additives and / or radiation-absorbing elements and / or components which change the refractive index can be added to the metal phosphate. These components are preferably inorganic. The metal phosphate may be, for example, aluminum phosphate, yttrium phosphate or another rare earth phosphate. The phosphate may in particular also additives, such as SiO 2, z. B. in the form of Aerosil, pyrogenic Al2O3, etc. may be added. These additives are preferably added as nanopowder, in particular their average particle size is in the range from 1 to 40 nm. Ground glasses such as hard glasses or ground glass solder can also be added as nanopowder. These additives may optionally increase the thermal conductivity again, serve as a reflector, or adjust the thermal expansion coefficient.

Also, an addition of radiation-absorbing components for targeted heating such. B. vanadium oxide and / or components with filtering action such. B. bismuth-containing compounds (with Bi) is possible. Other components are used specifically to change the refractive index, in particular Tellurhaltige compounds. The metal phosphate is moisture resistant and is preferably made at low temperatures. - This metal phosphate is also suitable for embedding of phosphors, so as a matrix for a conversion element. The proportion of additives can be so high that the metal phosphate serves primarily as a binder.

The application of the new adhesive leads to increased efficiency and increased service life. For this purpose, a bond or a component of metal phosphate, optionally with additives which are radiation-absorbing or reflective or refractive index-changing, is preferably used. This achieves an increase in the UV resistance, the thermal conductivity, an improvement in the temperature stability and possibly an increased refractive index.

Part or all of the added components may be selected to chemically react with and modify the metal phosphate.

Brief description of the drawings

In the following, the invention will be explained in more detail with reference to several embodiments. The figures show:

1 a LED with glass cover in cross section;

2 a LED with a lens in cross section;

3 an LED with conversion element in cross section;

4 a semiconductor device in section.

Preferred embodiment of the invention

1 schematically shows an LED 1 with a board 2 , On this sits a chip 3 , He is surrounded by a glass lid 4 with ceiling wall 5 and sidewalls 6 , In the side wall in particular ventilation slots are installed. The connection between side wall 6 and board 2 via a glue trace 10 , which is made of metal phosphate, which is preferably alkali-free and halogen-free.

2 schematically shows an LED 1 with board 2 and chip 3 , He is surrounded by a glass lid. This one is as a lens 11 executed, which is made of metal phosphate. It is over sidewalls 6 connected to the board, which also consists of metal phosphate. Between lens 11 and sidewall 6 on the one hand and between side wall 6 and board 2 On the other hand, an adhesive trace 10 of metal phosphate containing not more than 1 mole% of oxides of alkali and halogen elements. The Lens 11 itself is made of metal phosphate with up to 4 mol .-% of alkali oxides.

3 shows a chip 15 with conversion element 16 that the chip 15 is directly upstream. The conversion element 16 is a thin layer that uses metal phosphate as a matrix. Embedded therein are one or more phosphors, as known per se. Typical phosphors are YAG: Ce, Sione or also orthosilicates or calsines. In particular, they serve to generate white light with the aid of a blue or UV-emitting chip. In a particular embodiment of the embodiment of 3 are the phosphor particles bonded by the metal phosphate (bonding) or enclosed by this (protective layer). In the latter case, the thus passivated phosphor particles can also be present in a different matrix.

4 shows an optoelectronic semiconductor device 19 on average. The core is a primary UV-emitting chip 20 that with electrical connections 21 . 22 is connected, which are formed as ladder frame parts. One of the parts is over a bonding wire 23 connected to the chip. The chip 20 sits directly on a wide connector 21 that on the surface 25 a rectangular base made of glass (quartz, hard, soft glass or glass solder) or ceramic is arranged. On the body is an annular attachment 26 put on, which leaves a recess in his interior. The inner sloping wall 27 The attachment is shaped as a reflector. The tower is made with the base body and the lead frame made of the terminals by an inorganic adhesive 30 or solder glass connected. The adhesive is made of alkali-free and halogen-free metal phosphate. The essay 26 is also made of glass. The recess within the reflector is with a casting resin 31 filled, which includes a converting phosphor. Instead of the casting resin, a suitable metal phosphate may be used as the matrix. The LED is in particular finished with a cover plate and thus hermetically sealed.

In particular, the conversion element can be connected to the chip via a bond made of metal phosphate. However, the conversion element can also be applied directly to the chip as a so-called thin-film element.

The metal phosphate is low in alkali and halogen, preferably free of alkali and halogen. This means that these elements are not deliberately added and possibly result from contamination of the materials used. The concentrations of alkali metals and halogens are therefore immaterial and are each less than 1 mol .-%. As a result, internal components are reduced or completely avoided. In particular, this applies to internal-forming elements such as Na, Cl, K and F. These can namely reach the LED in the event of moisture, thereby attacking the contacts and also impairing the charge densities on the chip.

Instead of an LED, an OLED can also be used as an optoelectronic semiconductor component. There, the above considerations are at least as critical. Hermetic sealing of OLEDs is one of the big challenges.

The preparation of such metal phosphates succeeds, for example, via the known sol-gel process from a soluble metal phosphate or from the reaction product of an alkoxide with phosphoric acid or from the reaction product of metal salt with phosphoric acid with elimination of water. It is then present in polymerized form. Preference is given to using aluminum, yttrium or else one of the other rare earth phosphates, since such phosphates have high temperature resistance and good resistance to moisture.

The metal phosphate may be in amorphous, semi-crystalline or crystalline form.

The invention is not limited to this by the description with reference to the embodiments, but includes any novel feature and any combination of features contained in the claims, even if this Feature or combination itself is not explicitly given in the claims or exemplary embodiments.

• – anorganischer Kleber zur Befestigung des Konversionselements (z. B. Konverterkeramik u/o Leuchtstoff in Glas) auf dem Board;
• – anorganischer Kleber zur Befestigung der Linse auf dem Gehäuse;
• – anorganischer Kleber zur Befestigung des Glasdeckels auf einem Keramikboard;
• – anorganische Matrix eines Konversionselement in die der Leuchtstoff eingebettet ist oder durch die die Leuchtstoffpartikel miteinander verbunden sind;
• – anorganische Schutzschicht auf den Leuchtstoffpartikeln, die so passiviert werden und dann auch in eine andere Matrix eingebettet sein können;
• – reflektierende Komponente, die z. B. das teurere Titandioxid ganz oder teilweise ersetzt;
• – Linse;
• – Board/Gehäuse: Hier ist ein Metallphosphat mit Füllstoff vorteilhaft. Das Metallphosphat kann hier aber auch nur zum Verkleben von keramischen oder glasigen Partikeln eingesetzt werden;
• – Abdeckschicht des Konversionselementes, um dieses vor Umwelteinflüssen zu schützen;
• – funktionelle Beschichtung wie z. B. Antireflexionsschichten (Entspiegelung), die über dem Konversionselement liegt.

The presented metal phosphate according to the invention can serve as:

• - inorganic adhesive for fixing the conversion element (eg converter ceramic u / o phosphor in glass) on the board;
• - inorganic adhesive for fixing the lens to the housing;
• - inorganic adhesive for fixing the glass lid on a ceramic board;
• - Inorganic matrix of a conversion element in which the phosphor is embedded or through which the phosphor particles are interconnected;
• - inorganic protective layer on the phosphor particles, which can be passivated and then embedded in another matrix;
• - Reflective component z. B. the more expensive titanium dioxide completely or partially replaced;
• - lens;
• - Board / housing: Here is a metal phosphate with filler advantageous. The metal phosphate can also be used here only for the bonding of ceramic or glassy particles;
• - Cover layer of the conversion element to protect it from environmental influences;
• - Functional coating such. B. antireflection layers (anti-reflection), which lies above the conversion element.

It should be noted that the various functions of the metal phosphate are achieved by adapting its composition (essentially the Al 2 O 3-P 2 O 5 -H 2 O ratio) as well as the crosslinking during the temperature treatment to the respective application (transparency, turbidity, opacity). , In o. G. Cases, the metal phosphate may also contain glassy or ceramic fillers that do not melt with. The proportion of filler can be so high that the metal phosphate virtually acts only as a binder / adhesive that holds the filler particles, similar to a ceramic adhesive. Depending on the application and requirement, functional components may be added to the metal phosphate.

The thermal expansion coefficient of the metal phosphate is preferably at least 5.0 × 10 -6 / K.

The metal phosphate contains as the main component phosphate, which in various modifications, i. H. may be present as polyphosphate, metaphosphate, orthophosphate and in all possible intermediates.

In the following, concrete embodiments will be explained in more detail.

Example 1: Inorganic adhesive for fixing the conversion element

An aqueous solution of a metal phosphate z. B. Monoaluminum phosphate Al (H ₂ PO ₄ ) .nH ₂ O is applied as a thin layer on the chip and the conversion element is positioned on the wet layer. The application is carried out by the usual coating methods such as spin coating, screen printing, spraying, etc. Subsequently, the drying takes place at low temperatures (<150 ° C), optionally in addition at reduced ambient pressure and / or with a weight. The penetration, ie the condensation is in the temperature range of 150-800 ° C, preferably 200-400 ° C. Above 250 ° C then the triphosphate (AlH2P3O10) and above 500 ° C and 600 ° C long-chain and annular aluminum tetraphosphates.

The max. applicable baking temperature is given by the temperature resistance of the component components. Preferably, the penetration takes place at temperatures of 250-500 ° C, especially at 275-250 ° C.

Optionally, it is also possible to add to the suspension solids in powder form, preferably nanopowders such as, for example, fumed silica (eg Aerosil) and / or pyrogenic Al ₂ O ₃ (AluC) and / or pyrogenic TiO ₂ (P25), which are then removed from the Matrix are enclosed. Also possible is the addition of a ground soft, hard or quartz glass as well as a glass solder.

Another option is to add an aqueous solution of another soluble metal salt, such as yttrium acetate or yttrium phosphate, to the suspension. In this case, the components react with each other and the metal phosphate is thereby modified.

For fixing the lens on the housing and the glass lid on a ceramic board is similar procedure. Here is also possible the suspension radiation absorbing components such. As spinels, iron or vanadium oxide to enforce, which make it possible to heat the adhesive surface specifically with, for example, IR radiation.

Example 2: Inorganic matrix of a conversion element

In an aqueous solution of a metal phosphate according to Example 1, phosphor, for example YAG: Ce, is suspended in powder form and applied to the chip as a layer. Followed drying at low temperatures (<150 ° C), if necessary additionally at reduced ambient pressure. The firing takes place according to Example 1.

The solid content of phosphor can be varied depending on the desired color location of the LED. It is also possible to produce conversion elements that convert the light emitted by the chip to 100%. In this case, the solids content of phosphor is so high that the metal phosphate used encloses the phosphor particles only with a thin layer and thereby glued together.

It is also possible to embed a mixture of different phosphor powders in the metal phosphate in order to adjust different light colors.

Optionally, solids in powder form and / or solutions of other soluble metal salts may also be added to the suspension according to Example 1.

Example 3: Inorganic protective layer on the phosphor particles

In an aqueous solution of a metal phosphate according to Example 1, phosphor, for example YAG: Ce, is suspended in powder form and dried at low temperatures (<150 ° C.), if appropriate additionally under reduced ambient pressure. Subsequently, the solid mass is crushed and pulverized. The phosphor is now surrounded by a thin protective layer of metal phosphate. For the preparation of the conversion element, the phosphor particles are embedded with the now surrounding protective layer of metal phosphate in another matrix such as silicone or glass.

Optionally, the metal phosphate can also be previously polymerized by condensation according to Example 1.

Optionally, solids in powder form and / or solutions of other soluble metal salts may also be added to the suspension according to Example 1.

Example 4: Reflecting component

Complete or partial replacement of the reflective component titanium dioxide in the LED board by that in the patent DE 10 2007 031 960 A1 described aluminum orthophosphate dihydrate (preparation process and application).

Example 5: Lens

The aqueous, preferably concentrated solution of a metal phosphate according to Example 1 is poured into a mold made of, for example, metal, graphite or plastic or, alternatively, directly onto the cast conversion element. In the latter case, the convex shape sets over the wetting angle. Following drying at low temperatures (<150 ° C), if necessary, additionally at reduced ambient pressure. The firing takes place according to Example 1. The demolding from the casting mold can be carried out already after a medium baking temperature and then without mold at higher temperatures. Possibly. An after-treatment must be connected.

Optionally, solids in powder form and / or solutions of other soluble metal salts may also be added to the suspension according to Example 1.

Example 6: Board / housing

In an aqueous solution of a metal phosphate according to Example 1, an oxidic filler, for example, glass, ceramic or metal oxide is suspended in powder form and poured into a corresponding mold. Afterwards drying takes place at low temperatures (<150 ° C), if necessary additionally at reduced ambient pressure. The firing takes place according to Example 1.

The solids content of oxidic filler can be varied.

In a particular embodiment, the solids content of oxidic filler is so high that the metal phosphate used encloses the filler particles only with a thin layer and thereby glued together.

In a further particular embodiment, the suspension is free of fillers.

It is also possible to embed a mixture of different oxidic fillers in the metal phosphate.

Optionally, solids in powder form and / or solutions of other soluble metal salts may also be added to the suspension according to Example 1.

Example 7 Cover Layer of the Conversion Element

The conversion element is thinly coated with an aqueous solution of a metal phosphate according to Example 1 and dried at low temperatures (<150 ° C), optionally additionally at reduced ambient pressure. The firing takes place according to Example 1.

Optionally, the conversion element can also be cast with the metal phosphate.

As a further option, solids in powder form and / or solutions of other soluble metal salts may also be added to the suspension according to Example 1.

Example 8: Functional coating of the conversion element

According to Example 7. Preferably, it is dried and condensed here so that fine bubbles form in the layer, which reduce the refractive index, whereby an antireflection effect is generated.

In all examples, components with a filtering effect such as bismuth oxide or components which change the refractive index, preferably increase such as yttrium oxide or tellurium oxide, can also be added as soluble metal salts or as oxidic particles. The coefficient of expansion is preferably mentioned by particles as in Example 1 as well as by materials with a negative coefficient of expansion, for example β-eucryptite.

Preferably, the phosphates presented here are prepared via the sol-gel process. In general, a manufacturing process is often designed so that the starting materials are heated to over 250 ° C, condensed, then split off water, so that long chains form. Upon further heating, for example, monocyclic chains are formed. Al phosphate is formed at temperatures above 2600 ° C.

Concrete references can be found in detail in DE-A 101 13 287 and in J. Am. Ceram. Soc. In front. 39/3, pp. 89-98 (1956) ,

The term phosphates here explicitly also includes, in particular, mono-phosphate such as Al (H2PO4) 3 as well as polyphosphate such as [Al (H2PO4) 3] n. Depending on the processing, meta-phosphate such as AlP2O7 or tertiary phosphate such as AlPO4 may be formed. Orthophosphates are formed on treatment at temperatures above about 180 ° C, poly- and pyro-phosphates are formed when treated at temperatures above about 600 ° C. A clue is a relationship. of the phosphorus oxide [P2O5] to the metal oxide, for example [Al2O3], of 1:10 as a limit.

• 1. Optoelektronisches Halbleiterbauelement mit einer. Lichtquelle, einem Gehäuse und elektrischen Anschlüssen, wobei das optoelektronische Halbleiterbauelement eine Komponente aufweist, die Metallphosphat beinhaltet, dadurch gekennzeichnet, dass das Metallphosphat im wesentlichen alkalifrei und halogenfrei ist.
• 2. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass das Metallphosphat höchstens 1 Mol.-% an Alkalioxiden und halogenhaltigen Bestandteilen enthält.
• 3. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass das Metallphosphat als Hauptkomponente Phosphat enthält.
• 4. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass das Metallphosphat 5 bis 75 Mol.-% P2O5 und insbesondere 5 bis 25 Mol.-% Al2O3 oder Y2O3 enthält.
• 5. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass dem Metallphosphat jeweils zwischen 0,5 bis zu 10 Mol.-% an Vanadium V, Tellur Te und/oder Wismut Bi zugesetzt ist.
• 6. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass dem Metallphosphat anorganische Komponenten zugesetzt sind, die den Brechungsindex erhöhen und/oder als Füllstoffe dienen und/oder als optischer Filter wirken und/oder reflektieren und/oder entspiegeln und/oder Strahlung absorbieren.
• 7. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass die Komponente, die Metallphosphat enthält, ein Kleber als Verbindungsmittel zwischen zwei Bauteilen des Halbleiterbauelements ist.
• 8. optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass die Komponente, die Metallphosphat enthält, eine Matrix für ein Konversionselement ist.
• 9. optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass die Komponente, die Metallphosphat enthält, ein Gehäusebauteil oder eine Linse ist.
• 10. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass die Komponente, die Metallphosphat enthält, eine Schutzschicht für Leuchtstoffpartikel ist.
• 11. Optoelektronisches Halbleiterbauelement nach Anspruch 1, dadurch gekennzeichnet, dass die Komponente, die Metallphosphat enthält, eine Beschichtung oder Matrix einer Beschichtung des Konversionselementes ist.

Essential features of the invention in the form of a numbered list are:

• 1. Optoelectronic semiconductor component with a. A light source, a housing and electrical terminals, wherein the optoelectronic semiconductor device comprises a component which includes metal phosphate, characterized in that the metal phosphate is substantially alkali-free and halogen-free.
• 2. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate contains at most 1 mol .-% of alkali oxides and halogen-containing constituents.
• 3. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate as the main component contains phosphate.
• 4. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate contains 5 to 75 mol .-% P2O5 and in particular 5 to 25 mol .-% Al2O3 or Y2O3.
• 5. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate is added in each case between 0.5 to 10 mol .-% of vanadium V, tellurium Te and / or bismuth Bi.
• 6. The optoelectronic semiconductor component according to claim 1, characterized in that inorganic components which increase the refractive index and / or serve as fillers and / or act as an optical filter and / or reflect and / or antireflection and / or absorb radiation are added to the metal phosphate.
• 7. The optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is an adhesive as a connecting means between two components of the semiconductor device.
• 8. optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a matrix for a conversion element.
• 9. The optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a housing component or a lens.
• 10. The optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a protective layer for phosphor particles.
• 11. The optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a coating or matrix of a coating of the conversion element.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10118630 A [0002]
• DE 10159544 A [0002]
• US 5965469A [0002]
• DE 102007031960 A1 [0046]
• DE 10113287 A [0061]

Cited non-patent literature

• J. Am. Ceram. Soc. In front. 39/3, pp. 89-98 (1956) [0061]

Claims (11)

An optoelectronic semiconductor device having a light source, a housing and electrical connections, wherein the optoelectronic semiconductor component comprises a component comprising metal phosphate, characterized in that the metal phosphate is substantially alkali-free and halogen-free. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate contains at most 1 mol .-% of alkali oxides and halogen-containing constituents. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate as the main component contains phosphate. Optoelectronic semiconductor component according to Claim 1, characterized in that the metal phosphate contains 5 to 75 mol% P2O5 and in particular 5 to 25 mol% Al2O3 or Y2O3. Optoelectronic semiconductor component according to claim 1, characterized in that the metal phosphate is added in each case between 0.5 to 10 mol .-% of vanadium V, tellurium Te and / or bismuth Bi. Optoelectronic semiconductor component according to Claim 1, characterized in that inorganic components which increase the refractive index and / or serve as fillers and / or act as an optical filter and / or reflect and / or antireflective and / or absorb radiation are added to the metal phosphate. Optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is an adhesive as a connecting means between two components of the semiconductor device. Optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a matrix for a conversion element. Optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a housing component or a lens. Optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a protective layer for phosphor particles. Optoelectronic semiconductor component according to claim 1, characterized in that the component containing metal phosphate is a coating or matrix of a coating of the conversion element.

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